Flush-tank bulb



,F. T. ROBERTS. FLU SH TANK BU LB. APPLICATION FILED AUGJII 1.918.

Patented Aug. 26, 1919.

FRED THOMAS ROBERTS, OF CLEVELAND, OHIO.

FLUSH-TANK BULB.

Specification of Letters Patent.

Patented Aug. 26, 1919.

Application filed August 21. 1918. Serial No. 250,781.

To all whom it may concern:

Be it known that I, FRED THOMAS Ron- ERTS, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Flush-Tank Bulbs, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

This invention relates to flush tank bulbs or valve balls of the type wherein there is a comparatively stiff upper supporting portion carrying a comparatively flexible lower hemispherical portion adapted to seat in a discharge orifice. It is well known that the tendency of suction in a discharge pipe tends to collapse a valve ball, eventually distorting its shape and interfering with its accurate seating. Many attempts have been made to obviate the collapsing, for instance, a rigid uppersection has sometimes been provided, usually by This has disadvantages in that the ball will not seat as accurately if the orifice is not strictly round, and there are difficulties in making the proper connection between the metal upper portion and the rubber lower portion. Again a rubber upper portion has sometimes been reinforced by an interior rubber stiffener cemented to the wall, but here difficulties have been encountered from gas pockets which surfaces during vulcanization and prevented a tight connection, and it has been diflicult to obtain a tight seam between such upper and lower section. The result is that an unduly large proportion of valve balls heretofore manufactured has been discarded onv final inspection, thus causing in the aggregate a great loss to the manufacture.

I have found that I can obtain the desired comparatively stifi' but not rigid upper section and comparatively flexible lower section, effectively secured together, by making the upper section of die-pressed and semi-cured stock which becomes comparatively stifl, and by makin the lower section of approximately a hemisphere of soft flexible raw rubber, which directly abuts and makes a seam with the upper section, the two sections being provided with cement at the junction and then vulcanized together, the vulcanization setting the seam, curing the lower part and completing the curing makingit of metal.

formed at the cementedof the upper part. During such vulcanizat on fluid pressure is supplied to the interior, which keeps the article seated against the mold walls.

I prefer to form the upper section with the lower end of its wall cut off at an angle to the horizontal plane defining the bottom of a section and I embed this beveled edge into the raw rubber of the lower section. During vulcanization the internal pressure effectively presses the edge of the upper section outwardly against the embracing lower section and makes a very tight seam.

In the preferred form of my ball I cut off the end of the wall of the upper section to make an external conical surface at such an angle as will provide an overhang slightly greater than the thickness of the lower section. Then by pressing the upper section into the lower I can embed it therein and squeeze the edge of the upper portion into a thickened beveled form making a continuous junction with the upper sectionfor the full extent of the end face thereof and terminating substantially flush with it on the inside or outside or both. This gives a beveled seam of greater extent than the thickness of either section, whereby the parts may be very firmly and effectively united.

I prefer to make the upper section of a conical form whereby the desired stiffness may be obtained with a minimum amount ofrubber. may be of a comparatively cheap grade. If such cheap rubber is employed it may be unduly porous or rough, but the disadvantage of this can be readily overcome by putting a over the exterior of the upper section. When such veneer is used the lower section preferably extends across the ends of both the body of the upper section and the veneer, so that we have as before the flush engagement at the outer end of the seam.

A valve ball embodying the above mentioned characteristics is shown in the drawings hereof, and will now be more fully described.

Figure 1 is a side elevation of an approved form of my valve ball; Fig. 2 is a vertical central section through the salne; Fig. 3 is a plan of the valve ball; Fig. 4 is a vertical section through a similar ball ex- The rubber of the upper section thin veneer of high grade rubber cept that the upper section is provided with a thin veneer.

In the drawings, A indicates the lower hemispheral section, B the upper conical section, C the usual support-ing rod which screws into a threaded spud D embedded in the upper section. E indicates the outer edge of the beveled seam and F the inner edge. In Fig. 4 the veneer covering the upper section is designated G.

\Vhere a single-piece upper section is employed, it may have its bevel set back slightly to provide a short flange b, which extends across the upper edge of the lower section and makes the desired neat junction without requiring the lower section to come to a sharp edge. lVhere the veneer is used, its lower end may similarly overhang the end of the lower section as shown at g in Fig. 4.

In the manufacture of my ball a block of raw rubber stock is pressed between male and female dies into the form shown at B in Fig. 2, .the spud D having been held in the female dieand becoming embedded in the stock. If desired a veneer may be applied to this section. The comparatively soft hemispherical section A is suitably formed and cemented at the seam E F and the whole ball placed in a suitable vulcanizing mold and vulcanized while fluid pressure is supplied to the interior, for instance, by a heat expanding chemical placed within the ball before it derstood. 7

As to the manner of forming the lower section, it may be drawn into a mold cavity by suction, as set out in my application No. 190,383, filed September 8, 1917, in which case I prefer to make the mold cavity with an inward protuberance supporting the central portion of the section and preventing central stretching in the formation. During vulcanization the inwardly bowed portion becomes external and the section assumes the continuous convex shape shown in Figs. 2 and 4, and may be of substantially uniform thickness throughout. If the uniform thickness of the lower section is not required, this section may be made by simply securing sheet stock to the end. of the upper section and allowing the heat expanding chemical to stretch the stock into hemispherical form at the time of vulcanization, as set out in my prior application No. 198,620, filed October 26, 1917.

Where the veneer is desired it is preferable to seat it by a vacuum in a mold cavity having the contour of the exterior of the upper section, and then press the upper section with a firm contact against such veneer slfleet. In this operation a pin screwed into the spud D will furnish ready means for puncturin the veneer and provide an opening where y the suction may draw out the air between the body and the veneer, as well is joined, as is well un-" as leave a space for the insertion of the supporting rod C. This operation is described and claimed in my application No. 230,625 filed April 25, 1918.

In either of the three operations set out in the prior applications referred to, the two sections are brought together by coacting female dies which pinch the rubber together where the two sections join and shear ofl the surplus stock. In this pinching operation the end of the upper section B acts as a male die and embeds itself in the soft rubber of the lower section, squeezing the same outwardly against the mold wall and thus making an efiective seam. This is an important point, as it is at the seam where much of the difficulty with. prior balls has occurred. By beveling the seam as shown I not only obtain a seam of greater transverse dimension, but the penetration of the comparatively stiff upper member into the soft lower member squeezes the latter between itself and the mold wall, giving therefore a seam of not only greater area but of greater compaction than heretofore.

Having thus described my invention what I claim is 1. In an article of the character described, the combination of a flexible lower section and a less flexible upper section having its end seated within the lower section and making a lapped seam therewith, which extends across substantially the entire end of the less flexible section.

2. A hollow rubber article comprising a plurality of members directly united edge to edge to form an inclosing wall. one of said members being subjected to a materially greater amount of curing than another. the first mentioned member extending into the second member and having its entire end engage said second member.

3. A hollow rubber article having a flexible lower portion and an upper portion of less flexibility united to the lower portion by a beveledseam.

4. A flush tank bulb or similar article having a flexible lower substantially hemi-. spherical portion and an upper portion of less flexibility united to the lower portion by a beveled seam, the width of which is greater than the thickness of the lower section.

5. A flush tank bulb or similar article having a flexible lower portion, an upper portion of less flexibility united to the lower portion by a beveled seam, the width of which is greater than the thickness of the adjacent wall of either section, and a spud carried by the upper portion.

6. A flush tank bulb or similar article having a comparatively thin flexible lower substantially hemispherical portion, andan upper portion which is thicker and of f less flexibility and is united to the lower portion section.

by a beveled vulcanized seam, the width of which is greater than the thickness of either beveled edge and seating within the bevel of the lower section.

8. In an article of the character described, the combination of a flexible substantially hemispherical lower section having an inwardly beveled edge and a less flexible upper section having an outwardly beveled edge and seating within the bevel of the lower section, the greatest external diameter of the upper section being substantially equal to the greatest external diameter of the lower section, whereby a flush junction is obtained.

9. In an article of the character described, the combination of a flexible lower section having an inwardly beveled edge, and a less flexible upper section having an outwardly beveled edge and seating within the bevel of the lower section and having a slightly over-hanging portion which extends across the extreme edge of the lower portion.

10. In a flush tank bulb,- the combination of an upper section and a lower section, the end walls of which abut and engage each other in a beveled seam, the upper section having had a greater curing than the lower section. 1

11. In a valve ball, the combination of a substantially hemispherical lower section having an inwardly beveled upper edge, a conical upper section having the end of its wall contacting with such beveled edge and seating within it. s

12. A hollow rubber article consisting of a wall portion of comparatively thick material, a spud fitted therein, a wall portion having its edge united to the first named portion by a beveled seam and being of comparatively thinner material, the portion having the spud being cured through a longer period than the other portion.

13. As a new article of manufacture, a

hollow rubber body having a comparatively thick semi-cured portion, a comparatively thin veneer embracing the semi-cured portion, and a third portion which surrounds the edge of the semi-cured portion and engages its entire end, all three portions belng secured together by vulcanization.

14. As a new article of manufacture, a hollow rubber body having a semi-cured portion terminating in a beveled edge, a veneer embracing the semi-cured portion, and a third portion having its edge beveled and joining the edges of both the semi-cured portion and the veneer.

15. A hollow rubber article having a comparatively stifi' portion, a soft veneer e1n bracing the first portion, and a third portion of soft rubber completing the inclosure and having its edge joining the edges of both the comparatively stifi' portion and the veneer and extending across the entire end of the comparatively stifi portion.

16. In an article of the character described, the combination of a flexible substantially hemispherical lower section having an inwardly beveled edge, a less flexible upper section having an outwardly beveled edge and seating within the bevel of the lower section, and a veneer covering and adhering to the outer surface of the upper section, the end of said veneer abutting and joining the, extreme edge of the lower section.

17. A flush tank bulbor similar article having a flexible lower portion and an upper portion of less flexibility united to the lower portion by a beveled seam, and a spud carried by the upper portion.

18'. A flush tank bulb or similar article having a flexible lower portion andan upper portion of less flexibility united to the lower portion by a beveled vulcanized seam, and a spud in a thickened part of the upper portion, the latter being vulcanized to the spud.

19. A flush tank bulb or similar article having a comparatively thick semi-cured portion, a comparatively thin veneer emracing the semi-cured portion, and a third FRED THOMAS ROBERTS. 

